I. Field of The Invention
This invention pertains to an apparatus and a method of collecting bodily fluids from individuals. More specifically, the invention concerns an apparatus and a minimal to non-invasive method of collecting bodily fluids from individuals by inducing a suction blister and collecting the fluids accumulated therein.
II. Description of the Prior Art
The common conventional method of extracting bodily fluid from an individual utilizes a lancet or a needle to puncture the skin deep enough to allow the desired amount of fluid such as blood to be collected. Diabetics, typically must have periodic extractions of blood to measure for glucose. For diabetics, the fingertip is pricked with a needle and the same fingertip is squeezed to draw the necessary amount of blood. The blood is then placed on a test strip to analyze the glucose content. Often if the sample of blood collected is too small, the fingertip must be punctured again until enough blood is collected. A disadvantage with this conventional method is the pain involved in puncturing the skin especially in the area of the fingertip. The fingertip area is sensitive in that it contains a high concentration of nerve endings.
Another method and apparatus for extracting bodily fluid is taught in U.S. Pat. No. 5,879,310 issued to Sopp et al. According to the method in Sopp, a needle portion of a body fluid collection apparatus is protruded into an individual until it penetrates into a body fluid-laden skin layer. A sampler carried within the apparatus has an absorbent medium in fluid flow communication with the needle for body fluid to flow from the needle onto the medium. The disadvantages of such a method and apparatus is the pain involved in penetration with the needle and also the relatively high cost of such a device.
Thus, a system which allows bodily fluids to be extracted with very little or no pain is desirable.
It is a primary objective of the present invention to provide a minimal to non-invasive method and apparatus for extracting bodily fluids with the least amount of pain. It is yet another objective of the present invention to provide an apparatus for extracting bodily fluids which is relatively easy and inexpensive to manufacture.
The present invention provides a system which allows bodily fluid to be drawn not necessarily from the fingers as pricking a finger is known to be painful because of the high nerve ending concentration at the fingers. Instead the present invention allows bodily fluid to be drawn in a minimal to non-invasive manner from less painful areas of the body including the forearm, thigh, and upper arm.
In the present invention, bodily fluid is drawn using a suction module which has a hole extending from its top surface to its bottom surface. The bottom surface of the module adheres to the skin of the individual, and skin is drawn into the hole to form a blister by creating negative pressure within the hole. The blister containing bodily fluid therein is ruptured, and its fluid content is collected using a chemically treated testing strip which draws up fluid via capillary action. The testing strip containing the fluid is then tested to examine the fluid content. The fluid contained in the blister is usually interstitial fluid, and sometimes the fluid also contains blood. It is desirable to form blister containing only interstitial fluid.
The present invention is effective in testing for blood glucose level in diabetics using the interstitial fluid collected from the blister.